Rossner and Sohn Canofer-S Phono Preamplifier Review

As far as I know, the Canofer-S is the only phono stage that allows you to compensate for mismatched tonearm and cartridge compliance. Christoph should be commended for his meticulous attention to detail which is the mark of a true perfectionist!

At the end of many listening sessions, I was unable to detect any significant change in low frequencies by changing the dial on the five cartridge/tonearm combination that I tried with the unit. Detectable changes, if any, were very small. I suppose I can conclude that all my cartridges are properly matched with my tonearms. So I left the dial at the centre position. With the INCREASE dial taken out of the equation, it left me with 576 combinations rather than 13,842.

Finding the right combination for the remaining two dials was pretty straight forward. Of the five cartridges I tried with the unit, four required the highest or the second highest gain settings. The exception was the Kondo I/O-M cartridge which has an output of 0.12mv and required the use of a Kondo Step-up transformer. With each cartridge, I simply played a couple of LPs that I was familiar with and it became apparent very quickly which GAIN setting should be utilized. With the GAIN set at levels below 58dB, it simply wasn’t enough to drive for any of the cartridges. However, once you have found the proper gain setting, you’ll know it and nothing else will sound right. With proper gain, a few things happened: The overall presentation went from flat and boring to being dynamically charged. The holographic image solidified, instruments went from a faint haze to actual life size reproductions with weight and balance. The most noticeable difference was with the bass dynamics which exhibited more control and oomph. You will also notice that you will not need to crank up the volume too much to achieve the same level of detail.

The RESISTANCE dial was not difficult to use either. If one is concerned about doing things by the book, the correct setting is usually around 10x-20x the internal impedance of the cartridge. So for example, if your cartridge has an internal impedance of 10 ohms, the proper setting should be about 100-200 ohms. Personally, I ignore the numbers all together and adjust the setting through repeated listening. Basically, I throw a CD into the tray and play the same piece on vinyl, paying close attention to the high frequency presentation, while comparing it to the CD source which is used as a reference. If the dial is loaded down too much, such as with a setting which corresponds to the far left, the sound will become grey, lifeless and rolled off, with vocals becoming muffled. If loaded too high, the sound will become thin, bright and with the high frequencies exaggerated.

My own experiment tells me the optimal setting will fall within one to two dial positions. It did not take more than half an hour to find the optimal setting for each cartridge. The best part with the Canofer-S is that everything can be adjusted on the fly without having to turn off the unit or fiddle around with tiny internal dip switches. So, at the end you are really only playing with one-two settings on the RESISTANCE and GAIN dials rather than 13,842 possible combinations which is, in fact, somewhat misleading. The workings of the three rotary dials was much simpler to use than I initially thought.

I also noticed that the unit that I first saw at Lawrence Lock’s home has three sets of RCA connectors, but my unit only came with two. They are WBT terminals labelled INPUT and OUTPUT. According to Christoph, he had initially designed the unit with two inputs in mind, but after a full year of experimenting with different input switches, he was unable to find any switches that do not adversely affect the input signal. Because the switch must be placed in front of signal amplification, it will be handing the exceedingly small incoming signal directly from the cartridge, so any additional switch will degrade the sound quality. For this reason, the Canofer-S is only fitted with one input. The third set of inputs on Lawrence’s unit were actually a set of dummies that were not connected internally.